Coke oven



Nov. 22, 1932. LAMBERTZ 1,888,926,

COKE OVEN Filed May 11, 1925 3 Sheets-Sheet 1 NOV. 22, 1932. LAMBERTZ1,888,926

COKE OVEN Filed May 11, 1926 3 Sheets-Sheet 2 G. LAMBERTZ 1,888,926

com: ovsn Filed May 11. 1926 3 Sheets-Sheet 3 Nov. 22, 1932.

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Patented Nov. 22, 1932 UNITED STATES FATE OFFICE GUSTAV LAMBERTZ, OFREGKLINGHAUSEN, GERMANY, ASSIGNOR TO CARL STILL, OF REGKLINGHAUSEN,GERMANY COKE OVEN Application filed May 11, 1926, Serial No.

My invention relates to improvements in coke ovens for the drydistillation or carbonization of coal at high temperatures, especiallycoke ovens of this kind having high and relatively narrow cokingchambers, the main object being to ensure as great a yield as possibleof by-products and the production of coke of best quality. Other objectswill hereinafter appear from the following description and annexedclaims.

Repeated attempts have been made in the dry distillation of fuels inclosed chambers or retorts, in such ones also of great height andrelatively small width, to remove all of the volatile products ofcarbonization at a point near the bottom of the chamber, for instance bymeans of pipes hanging in the charge vertically from above, or by hollowspaces provided in the bottom part of the charge, or by like means. Bythis method of operation an improvement in the quality and yield of theproducts of carbonization, especially of the hydrocarbons was expected,because it was assumed that by being removed in a downward directionthey would preferably have to find their way through the middle coolerportion of the charge and thus avoid the disadvantages due to thedestructive influences of the hot oven walls. However, the hoped foradvantages did not materialize in practice, or only partly, andtherefore this method of operation has found but little application.

Now my invention is based on the novel discovery that these failuresexperienced in the removal of the gases downwards was due to the fact,that the influence which the heating of the chambers or retorts exertson the internal process of the chamber was overlooked.

For illustrating both the prior art and the novel features of myinvention reference will be made to the accompanying drawings in whichall the Figures 1, 2, 3 represent similar cross sectional elevations ofhorizontal coke ovens with vertical heating flues, each comprising onecoking chamber and two adjacent heating walls. Herein the Figs. 1 and 2refer to usual and known arrangements,

108,314, and in Germany May 13, 1925.

whereas the Fig. 3 shows an arrangement according to the invention.

In order to make clear my invention and to explain its base, firstly theknown process of carbonization in a coke oven, heated and operated inthe usual manner with removal of the products of carbonization at thetop of the chamber may be described with reference to the Fig. 1 asfollows:

According to the generally accepted opinion strengthened by experience,there are, in a coal charge subjected to carbonization, two layers a(of. Fig. 1) of small thickness (30 to 40 mm) running parallel to thetwo heating walls, consisting of coal in the plastic stage, whichcontains much tarry and bituminous matter and forms a foamy mass; thetwo layers a, usually called plastic stage zones or coking seams travelaccording to the progress of carbonization towards each other andfinally meet at the oven centre. On the inside between these two layers,lies raw, unconverted coal 6 with an initial temperature of about 100C., which is slightly increased later; on the two outsides there remainsthe finished coke a of high temperature (about 900 to 1000 C.) and ofvery strong and dense structure interspersed with a network ofhorizontal and vertical fractures of varying depth, but generally notreaching the plastic stage zones. Between the coke c and the walls dowing to the shrinking of the coke a narrow fissure 8 is formed alongthe full area of the wall.

The plastic stage zone or coking seam a is undoubtedly the place wherethe chief products of carbonization including water vapour are formed.The gases and vapours here liberated naturally tend to travel away fromthe dense coke 0 to the loose, low resisting raw coal 6 and for thisreason a permanent advancing of gases and vapours from the plastic stagezones (1 to the interior space 6 will take place.

In the oven chamber therefore a relatively cool column of continuouslyrenewed gas I) consequently of higher specific gravity, and two very hotcolumns of gas 0 of much lower specific gravity, coexist. Such a systemcannot be in equilibrium. On the contrary, a circular flow between I)and c arises and exists, downwards through I) and upwards through 0,because the separating layers, i. e. the plastic stage zones naturallycannot form absolutely hermetically sealed joints, particularly at thebottom of the chamber. This flow within the oven chamber is shown inFig. 1 by arrows.

There is no doubt, that, in the lower part of the oven chamber, owing tothe greater weight of the gas column b, freshly produced cool gases andvapours from I; pass through the leakages of the plastic stage Zones atowards the heated chamber walls d. These passing gases and vapours actas a cooling agent to the hot walls cl, become heated and, owing to thebuoyancy obtained, rise along the walls through the existing fracturesof the coke c and the fissures s upwards and are only thereafter removedthrough the opening 6 in the roof of the chamber. While passing throughthe incandescent coke c and along the highly heated walls at many usefulby-products contained in the gases and vapours are cracked anddestroyed, and therebythe quality and yield of such byproducts isdiminished, which is a result well experienced in practice.

Obviously, however, the described current of the gases within the chargeand especially within the lower part thereof, which current causestheundesired overheating of the gases, simultaneously serves as a means ofequalizing the differences of the rate of heating due to the usualmethods of heating which have been dealt with in Fig. 1. If, as it iscustomary, the total amounts of both heating gas and air for combustionare supplied at asingle point at the base of the heating flues as shownin Fig. 1, then a very high temperature of about 1500 C. and more exists'at this point ofcombustion, as the fusion of the brickwork which oftentakes place at this point indicates, but a lower temperature of about1100 C. will be found at the top of the heating flue, whilst atemperature of 900 to 1000 C. for the finished coke in the chamber wouldbe suflicient. Under these conditions the distillation and carbonizationat the bottom of the charge proceeds more rapidly than in the upperparts. As a consequence, the plastic stage zonesor coking seams a whichare assumed'as parallel in Fig. 1 really advance quicker at the lowerthan at the upper parts and meet each other in the centre of the chargeearlier at the bottom than at the top. This irregularity has also beenproved by actual experience. However, it has been overlooked that theinfluence of the flow of gas within the oven chamber diminishes thisirregularity which would be greater and more injurious if that influencewould be absent.

Now, when it is assumed that the gases and vapours in a coke ovenreferred to above and shown by Fig. 1 are removed from the lower part ofthe charge instead of at its top, then not only is the flow of gaswithin the charge itself changed but as a consequence, and in aremarkable manner, the influence of the heating also. This discovery andits useful application are new and most important, and form the base ofthe present invention. Therefore, a detailed explanation also of thesaid modification of the known method of operation described before andshown by Fig. 1 will be given in the following with reference to Fig. 2.The method illustrated by this Fig. 2 contrasts the method employed inFig. 1 thereby that, instead of removing from the chamber the gases andvapours through an opening in the chamber roof, in the case of Fig. 2 aperforated pipe 7" arranged near the bottom of the coking cha1nber isprovided for the same purpose.

The flow of gas in the lower part of the charge as shown in Fig. 1, i.e. from I) through a and towards c is impossible in Fig. 2 owing to apoint of minimum pressure at the pipe 7" having been created, or whatamounts to the same thing, owing to the direct drain of the descendinggas column Z) through the pipe 7'. Contrariwise to Fig. 1, even thegases produced within the coke layer 0 at the end of the coking period(especially hydrogen) will flow in the neighbourhood of the exhaust pipe1' from 0 through leakages of or towards b. In the upper part of thecharge, where the direct influence of the exhaust pipe 1" is diminished,

partial quantities of gas will perhaps pass from I) through a towards 0and travel circularwise as shown in the drawings. But this flow can beonly very slight owing to the small height of gas columns and the lowpressure differences arising therefrom.

With the change of the flow of gases 1n the lower part of the ovenchamber referred to in Fig. 2 the heat-equalizing influence of the flowof gas on the unequal heating of the chamber wall d, as explained beforewith reference to Fig. 1, must necessarily cease. The higher heat causedby the flames in the lower part of the charge will act and prevail farmore intensively than with the usual method corresponding to Fig. 1. Theplastic stage zones a approach each other at the bottom far quicker thanat the top of the charge and finally meet at the exhaust pipe 'r' longbefore doing so in the upper part and, after the coking process hasproceeded but a short time, there appears a trough-like formation of thesaid zones as shown by the dotted lines a in Fig. 2.

This condition indicates that the exhaust pipe 1" is entirely surroundedby finished incandescent coke. Thus all the gases and vapours producedmust consequently penetrate the incandescent coke before entering thepipe 1". In this case even a large quantity of the charge will flowalong the heated chamber wall, at any rate over a part of it, becausehere the least resistance is offered and the travel of the gas is mostconvenient. Already before the condition shown by a of the plastic stagezones has arisen, the flow of gas will be modified in the mannerdescribed and the gases and vapours will pass, at least partially, inthe neighbourhood of the pipe '7' through the incandescent coke, as soonas the two plastic stage zones meet at this point in the centre of thechamber. Given such conditions of flow of gas in the chamber, naturallyall those disadvantages and dangers referred to above occur again, whichare customary when removing the gases upwards but which ought to beavoided by removing them downwards and through the centre of the charge.The said premature progression of the coking process that occurstherefore in the lower section of the chamber due to the defects in theusual method of heating, has been recognized by the inventor as thecause of the failures in former attempts to carry away the gases in adownward direction.

After having explained before the usual and known methods of operatingcoke ovens of the kind referred to and after detecting and clearing upthe failures of the same, the

. followin descri )tlOD of in invention and its effects will be easilyunderstood. For this purpose, reference is made to Fig. 3 of the annexeddrawings.

Briefly stated, my invention consists in the combination of means forthe removal of the volatile gaseous products of carbonization from thebottom of the chamber or retort with means for controlling the heatingof the chamber walls as to the vertical direction, which controlling isaccomplished in such a manner that a substantially uniform heating overthe entire height of the chamber is achieved and that in the vicinity ofthe draw-off point of the gases a premature process of coking. asdescribed in Fig. 2, becomes impossible.

Naturally, the said means required for heating must ensure within theheating tines a complete control of the flame tmnperatures over thetotal height of the heating wall witl'iout being affected by accidentalinfluence. An excellent means free from all objections tziat can beadopted for this purpose is explained in the patent application PetschSer. No. 724,708, filed July 7, 1924, and that has been made use of inthe coke oven to be described by the following.

For drawing off the volatile gaseous prod nets of carbonization inaccordance with Fig. 3, a perforated pipe 1", situated near the chamberbottom, is provided, which, however. could be replaced by any equivalentmeans. The vertical heating flues are heated by gas entering at the basein the same manner as shown in Figs. 1 and 2 through a gas distrib- 65uting main h and nozzles f at the bottom of each heating flue. The airfor combustion is conveyed by a sole-flue is into passages 71, marranged within the binder walls which separate the single fines andenters the heating flues at dilferent levels by a plurality ofsuperimposed outlets n. By correctly dimensioning these outlets n, asexplained in the said patent application Ser. No. 724,708, the heatingof the chamber walls over their total height is practically uniform andcan be controlled without trouble. Experience has shown that byemploying this method of heating the temperature of the wall surfacesdirectly acted on by the flames seldom differ from each other by morethan a few degrees centigrade at any point. Such a uniform verticalheating naturally ensures an equal progression of the plastic stagezones (is. Therefore, any premature coking of the bottom part of theoven charge is rendered impossible by employing the means described inthe said patent application.

By suitably modifying the dimensions of the air outlets it is evenpossible to introduce a relatively greater quantity of air in the upperpart of the flues than necessary for a quite uniform heating and therebyrender the heating still substantially uniform but rather weaker at thelower than at the upper parts, which method retards moderately theprogress of coking in the lower part of the chamher. In this case theplastic stage zones will meet somewhat earlier in the upper part than inthe lower part. Chamber or retort ovens operated in the usual manner byremoving the gases upwards through the roof and supplied with greaterheat in the top sections are considered disadvantageous on account tothe overheating of the ascending gases and vapours. By removing thegases and vapours downwards as herein proposed, however, suchconsiderations do not arise. On the contrary the higher rate of heatingin the upper part and the diminished rate in the lower part of thechamber brings advantages to the suction of the gas because by thismeans an uninterrupted flow of the gases and vapours arising from theplastic stage Zones will be assured through the centre of the chargetowards the draw-off point which flow takes place practically over thetotal area of the charge and during the full period of coking.

From the above description it is evident that the downward suction ofthe volatile gaseous products of carbonization through the interior ofthe oven charge and their draw-off at or near its bottom can only bepractically and successfully achieved by combination with means foruniform and easily controllable vertical heating. Only by thiscombination which avoids surely the premature coking of the bottom partof the charge and the resulting stoppage of the draw-off point byincandescent coke the effect is obtained that the gaseous distillationproducts will be led 0E without any obstruction and damage and withuseful saving of the valuable by-products.

The invention is not limited to the special constructions described andshown. For example, the peculiarity of arranging vertical heating fluesis in no way a necessary condition for constituting the invention. Anymeans which ensured the control and uniformity of the heating of thechamber wall as to the vertical direction, when combined with means fordrawing oif gaseous products of distillation at or near the bottom ofthe chamber, fall within the scope of this invention.

lVhat I claim is:

1. In an intermittently operable horizontal coke oven, a coking chamber,vertical heating flues, means for feeding combustible gas to said fluesadjacent the base thereof, means for supplying the total combustion airin several definite portions to said flues at different levels above thegas inlet, required to produce a gradual combustion and nearly uniformheating throughout the length of the flues, in combination with meansfor drawing off gaseous distillation products adjacent he bottom of saidcoking chamber.

2. In an intermittently operable horizontal coke oven, a coking chamber,vertical heating flues, means for feeding combustible gas to said fluesadjacent the base thereof, means for supplying the total combustion airin several. definite portions to said flues at different levels abovethe gas inlet, required to produce a gradually increasing combustion anda nearly uniform heating throughout the length of the flues, incombination with means for drawing off gaseous distillation products,adjacent the bottom of said coking chamber.

3. In an intermittently operable horizontal coke oven, a coking chamber,vertical flues defined by walls certain of which are pro- 1 vided withvertical air passages having outlets adapted to discharge into the fluesat different levels in each of said flues, the cross sectional areas ofsaid outlets increasing from the base of the flue toward the exit endthereof, and means for feeding gas to the base of the flues, incombination with means for drawing off from all levels of the chambergaseous distillation products adjacent the bottom of said cokingchamber.

In testimony whereof I affix my signature.

GUSTAV LAMBERTZ.

